The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
The speed of optoelectronic devices has increased by several orders of magnitudes during the last few decades and has surpassed the top speed of electronic circuits. Despite the ability to carry more than 1 Terabit-per-second of information with optical waves and a potential bandwidth greater than 1 THz, fundamental limitations of signal storage and processing in the optical domain have restricted the use of high speed optoelectronic devices. Signal storage and processing in the optical domain may simplify optical system architectures and enable higher speed. With the current device architectures, slower-speed electronics and complex optical electrical-optical (O/E/O) conversion are required to perform computation.
Despite the development of several all-optical logic gate architectures, the lack of a practical optical information storage technology makes sequential binary operations using these devices very difficult and thus severely limits the computational scaling capability. Although a variety of techniques including fiber optic loop, slow light, and nonlinear photonic crystal have been proposed to achieve optical information storage, these devices are either too bulky or hard to scale to the desired capacity.
For example, there is a fundamental bandwidth-delay product tradeoff for slow-light-based optical information storage, which in many cases will limit the storage capacity to only a few digital bits. Although it is possible to increase the storage capacity by using parallel device connections or a multi-spectral component pump source, these approaches are themselves very complicated and challenging.